Pre heat oven to 200c.
In a jug, combine the cream (200ml) and buttermilk (200ml), then set aside.
Place self raising flour, (3 cups/450g), caster sugar (2½ tbsp), sultanas (1¼ cups/215g) and cinnamon (a pinch) into a large bowl, and mix to combine.
Add cream and buttermilk mixture to the bowl with the flour, and mix to combine using a flat bladed knife. For the final few strokes, I bring the dough together with my hands.
Turn the dough out onto a floured bench/board and knead the dough lightly until just smooth - should only need about 30 seconds or about 5 - 10 turns. Pat the dough out into an even 2½cm / 1" thick disc.
Take a 6cm / 2 1/2" round scone cutter, dip it in extra flour and cut out scones. Try not to twist the cutter as you push down and then pull back up through the dough. Nice clean cut edges will help your scones rise (see my notes).
Remove any excess dough from around the scones (try not to squish the edges) then place onto a baking tray - again trying not to handle the edges of the scones. Push together the remaining dough scraps and repeat (see notes).
Bake for 12 - 15 minutes, or until the tops are golden and they sound hollow when you tap them.
Serve with jam and whipped cream.